From 22ac627fd3a02c2e2c4b53dfecfaf409d8324b10 Mon Sep 17 00:00:00 2001
From: Aaron Schulz <aschulz@wikimedia.org>
Date: Thu, 4 Oct 2012 11:43:59 -0700
Subject: [PATCH] Added "posdump" option to syncFileBackend to dump the current
 position.

Change-Id: Iabb027788796e98e06e3c6e97d14f74819cc6c95
---
 .../filebackend/filejournal/DBFileJournal.php | 13 +++++++++
 .../filebackend/filejournal/FileJournal.php   | 27 +++++++++++++++++--
 maintenance/syncFileBackend.php               | 27 +++++++++++++++++--
 3 files changed, 63 insertions(+), 4 deletions(-)

diff --git a/includes/filebackend/filejournal/DBFileJournal.php b/includes/filebackend/filejournal/DBFileJournal.php
index f6268c258f..34f3e53d50 100644
--- a/includes/filebackend/filejournal/DBFileJournal.php
+++ b/includes/filebackend/filejournal/DBFileJournal.php
@@ -83,6 +83,19 @@ class DBFileJournal extends FileJournal {
 		return $status;
 	}
 
+	/**
+	 * @see FileJournal::doGetCurrentPosition()
+	 * @return integer|false
+	 */
+	protected function doGetCurrentPosition() {
+		$dbw = $this->getMasterDB();
+
+		return $dbw->selectField( 'filejournal', 'MAX(fj_id)',
+			array( 'fj_backend' => $this->backend ),
+			__METHOD__
+		);
+	}
+
 	/**
 	 * @see FileJournal::doGetChangeEntries()
 	 * @return Array
diff --git a/includes/filebackend/filejournal/FileJournal.php b/includes/filebackend/filejournal/FileJournal.php
index ce029bbeaf..3bc0df74f5 100644
--- a/includes/filebackend/filejournal/FileJournal.php
+++ b/includes/filebackend/filejournal/FileJournal.php
@@ -110,6 +110,21 @@ abstract class FileJournal {
 	 */
 	abstract protected function doLogChangeBatch( array $entries, $batchId );
 
+	/**
+	 * Get the position ID of the latest journal entry
+	 *
+	 * @return integer|false
+	 */
+	final public function getCurrentPosition() {
+		return $this->doGetCurrentPosition();
+	}
+
+	/**
+	 * @see FileJournal::getCurrentPosition()
+	 * @return integer|false
+	 */
+	abstract protected function doGetCurrentPosition();
+
 	/**
 	 * Get an array of file change log entries.
 	 * A starting change ID and/or limit can be specified.
@@ -169,7 +184,7 @@ abstract class FileJournal {
  */
 class NullFileJournal extends FileJournal {
 	/**
-	 * @see FileJournal::logChangeBatch()
+	 * @see FileJournal::doLogChangeBatch()
 	 * @param $entries array
 	 * @param $batchId string
 	 * @return Status
@@ -178,6 +193,14 @@ class NullFileJournal extends FileJournal {
 		return Status::newGood();
 	}
 
+	/**
+	 * @see FileJournal::doGetCurrentPosition()
+	 * @return integer|false
+	 */
+	protected function doGetCurrentPosition() {
+		return false;
+	}
+
 	/**
 	 * @see FileJournal::doGetChangeEntries()
 	 * @return Array
@@ -187,7 +210,7 @@ class NullFileJournal extends FileJournal {
 	}
 
 	/**
-	 * @see FileJournal::purgeOldLogs()
+	 * @see FileJournal::doPurgeOldLogs()
 	 * @return Status
 	 */
 	protected function doPurgeOldLogs() {
diff --git a/maintenance/syncFileBackend.php b/maintenance/syncFileBackend.php
index a29647b50a..e279ccb1f3 100644
--- a/maintenance/syncFileBackend.php
+++ b/maintenance/syncFileBackend.php
@@ -34,21 +34,44 @@ class SyncFileBackend extends Maintenance {
 		parent::__construct();
 		$this->mDescription = "Sync one file backend with another using the journal";
 		$this->addOption( 'src', 'Name of backend to sync from', true, true );
-		$this->addOption( 'dst', 'Name of destination backend to sync', true, true );
+		$this->addOption( 'dst', 'Name of destination backend to sync', false, true );
 		$this->addOption( 'start', 'Starting journal ID', false, true );
 		$this->addOption( 'end', 'Ending journal ID', false, true );
 		$this->addOption( 'posdir', 'Directory to read/record journal positions', false, true );
+		$this->addOption( 'posdump', 'Just dump current journal position into the position dir.' );
 		$this->addOption( 'verbose', 'Verbose mode', false, false, 'v' );
 		$this->setBatchSize( 50 );
 	}
 
 	public function execute() {
 		$src = FileBackendGroup::singleton()->get( $this->getOption( 'src' ) );
-		$dst = FileBackendGroup::singleton()->get( $this->getOption( 'dst' ) );
 
 		$posDir = $this->getOption( 'posdir' );
 		$posFile = $posDir ? $posDir . '/' . wfWikiID() : false;
 
+		if ( $this->hasOption( 'posdump' ) ) {
+			// Just dump the current position into the specified position dir
+			if ( !$this->hasOption( 'posdir' ) ) {
+				$this->error( "Param posdir required!", 1 );
+			}
+			$id = (int)$src->getJournal()->getCurrentPosition(); // default to 0
+			$this->output( "Current journal position is $id.\n" );
+			if ( file_put_contents( $posFile, $id, LOCK_EX ) !== false ) {
+				$this->output( "Saved journal position file.\n" );
+			} else {
+				$this->output( "Could not save journal position file.\n" );
+			}
+			if ( $this->isQuiet() ) {
+				print $id; // give a single machine-readable number
+			}
+			return;
+		}
+
+		if ( !$this->hasOption( 'dst' ) ) {
+			$this->error( "Param dst required!", 1 );
+		}
+		$dst = FileBackendGroup::singleton()->get( $this->getOption( 'dst' ) );
+
 		$start = $this->getOption( 'start', 0 );
 		if ( !$start && $posFile && is_dir( $posDir ) ) {
 			$start = is_file( $posFile )
-- 
2.20.1